In recent years, in classifier learning methods, a learning method is proposed in which persons gives respective learning samples in learning data in advance with attributes corresponding to the learning sample to thereby learn a two-class classifier which is a classification metric for classifying given attributes. Examples of the attribute given to learning samples include gender and the like if the learning samples are the images of person's face.
In the learning method, respective learning samples are given with various attributes in advance to thereby learn a two-class classifier of each of the given attributes. Moreover, a plurality of learned two-class classifiers are used for object recognition or the like, with the output values of the respective two-class classifiers being used as feature amounts of objects.
However, in the technique of the related art, persons have to give the learning samples with attributes, which incurs a cost.